This invention relates to gas turbine or jet engines, and, more particularly, to gas turbine or jet engine stator vane frames.
As is known, the inner surface of a compressor casing, in gas turbine or jet engines, is machined with circumferential T-section grooves to retain stator blades therein. Engines also include variable outlet guide vanes to direct flow alignment. In this case variable vane bearing seats are formed by radial holes and counterbores through circumferential supporting ribs. Stator blades are locked in the compressor casing, forming a platform either directly through T-grooves or by retaining rings. In order to efficiently use the compressed air flowing through the vanes, the casing needs to be suitably sealed. Also, vane vibration results in platform deflection, which causes shearing motion relative to separate and integral part of a stator vane frame assemble. A gasket is provided around the frames to seal the air path. However, the low damping effect of the vane frame can lead to vibratory stresses which exceed material strength, and which may result in vane cracking and other failures.
In an exemplary embodiment of the invention a stator vane frame assembly includes an outer structure ring, an inner structure ring, a set of vanes connecting the outer structure ring and the inner structure ring, that forms inner and outer platforms, a set of flow paths, a set of sealing members contoured to a set of gaps between the set of vanes disposed to sealing the gap. Also, a spacer in between the frame and the vane platform is eliminated in that the sealing members perform the function of the spacer.
In addition, vibratory stresses are reduced by the damping effect caused by the introduction of sealing members disposed to seal individual or discrete vanes. Each individual vane is connected together with some other members of the set of vanes. Gaps between the vanes are sealed on the backside by a sealing member to enhance a damping effect so that metal fatigue of the relevant metal parts is reduced. Also, vane cracking and other failures are reduced as well. In addition, the added damping provided by the sealing members increases the fatigue life of the vanes, as well as permitting the use of lower strength, lighter, and less expensive materials.